1. Field
The described technology relates generally to an organic light emitting diode (OLED) display, and to a manufacturing method thereof.
2. Description of Related Art
An organic light emitting diode (OLED) display includes a hole injection electrode, an electron injection electrode, and an organic emission layer formed therebetween that emits light as holes injected from an anode and electrons injected from a cathode are recombined to become extinct at the organic light emission layer. The organic light emitting diode (OLED) display device, which has high quality properties such as low power consumption, high luminance, a high reaction speed, and the like, is receiving much attention as a next-generation display device for mobile electronic devices.
The organic light emitting diode (OLED) display includes an organic light emitting display panel including a display substrate on which thin film transistors and organic light emitting diodes (OLEDs) are formed. The organic light emitting diode includes an anode, a cathode, and an organic emission layer. Holes and electrons are injected from the anode and the cathode, respectively, to form excitons, which make a transition to a ground state, thereby causing the organic light emitting diode to emit light.
The organic light emitting diode formed with an organic material may have deteriorated performance when exposed to moisture or oxygen, and therefore, an encapsulation technique is used in the organic light emitting display panel to reduce or prevent deterioration due to moisture and oxygen.
With the thin film encapsulation technique, one or more of inorganic and organic layers are alternately deposited on the organic light emitting diodes formed at the display area of the substrate, thereby covering the display area with a thin film encapsulation layer. With the OLED display having such a thin film encapsulation layer, if the substrate is formed with a flexible film, it can be more easily bent, and is advantageous in forming a slim structure.
However, when depositing an organic film on the substrate on which the organic light emitting diodes are formed, a liquid monomer can be deposited on the substrate, and can be hardened by using electron beams or ultraviolet (UV) rays. In this instance, the organic film is deposited in a liquid state so spreading over the deposition area set by a mask may occur at an end of the organic film, that is, an edge area of the organic film. When inorganic film is formed without considering the part that is generated due to the spreading phenomenon, the end part of the organic film is not completely sealed by the inorganic film, but is instead exposed. In this case, the organic film allows for a moisture permeation path of external moisture and oxygen to deteriorate performance of the organic light emitting diode (OLED) display, and a non-display defect, which is referred to as “dark spots,” can occur. When the deposition area of the inorganic film is extended more than needed to prevent the above-noted problem, a “dead space” of the display device is increased.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.